Process for breaking petroleum emulsions



Patented Feb. 1, 1944 I UNITED STATES. PATEN T oFFic PROCESS FOR. BREAKING PETROLEUM EMULSIONS Melvin De Groote, University City, Bernhard Keisenwebster Groves, and Arthur F. Wirtel, Kirkwood, Mo., assignors to Petrolite Corpo'ra-' tion, Ltd., Wilmington, Del., a. corporation of Delaware No Drawing. Application April 27, 1942,

Serial No. 440.750

5 Claims. (Cl. 252-340 rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude petroleum and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned is of significant value in removing impurities, particularly inorganic salts, from pipeline oil.

The composition of matter employed as the demulsifier of our process, is obtained by the hydroxyacetylation of blown or oxidized ricinoleic the saponification value.

acid compounds, or compounds of the kind here inafter described.

It is well known that oxidized oils can be obtained from castor oil, ricinoleic acid and various derivative of ricinoleicacid, such as: Monori'cinolein, diricinolein and polyricinoleic acids. They are produced by the common practice of blowing or oxidizing castor oil and similar fatty oils or acids, particularly non-drying unsaturated fatty oils, by means of a gaseous medium, such as air, oxygen, ozone, or ozonized air. The gaseous medium, such as air, may be moist or dry, and the oxidation may take place in the presence or absence of a catalyst. The catalyst may be of a metallic type. such as lead ricinoleate. cobalt ricinoleate, manganese ricinoleate, etc.; or it may be of the organic type which produces peroxide such as alpha-pinene, linseed oil, etc. Oxidation may take place at atmospheric pressure or superatmospheric pressure, 1. e., pressures up to or including 200 pounds gauge pressure, and at any temperature slightly above the boiling point of water, for instance, 120 C., up to any temperature which does not produce undue decomposition by pyrolytic reaction.

The time of blowing may be fairly brief, for example, 8-10 hours; or it may be quite extensive, for instance, as long as 10-12-14 days, the longer time periods being employed generally when the temperature is Just slightly abov the boiling point of water and when oxidation is with air at atmospheric pressure.

oxidation. 1. e., oxidation as exemplified by the exposure of a film of castor oil to air, for an extended period of time, such as weeks or even months (see Chemical Technology and Analysis of Oils, Fats, and Waxes, by Lewkowitsch, sixth edition, volume 2, page 406) produces relatively small. modifications of certain important indices, such as the iodine value, the acetyl value, and If drastic oxidation takesplace, either by continued mild oxidation, or by more vigorous oxidation from the very beginning of'the reaction, as induced by either a higher reaction temperature or the presence of a "catalyst, then there is obtained an oxidized oil having characteristics which clearly indicate that drastic oxidation has taken place. These indices of drastic oxidation are a relatively low iodine value, such as or less, and may be as low as 40, or thereabouts; a saponification value of 215 to 283, or thereabouts; an acetylvalue of approximately--200; an increased viscosity such that the material may be hardly mobil at ordinary temperatures; a specific gravity of almost one, or

a trifle over one at times; an increased refractive index; and, in the absence of other coloring matter, a yellow to deep orange color. The color at times may be a questionable index, since some oxidized castor oils are bleached to make them particularly adaptable for use as plasticizers in light colored resinoid bodies.

Drastically-oxidized castor oil can be prepared by well known methods, or such products can be purchased in the open market under various trade names, such as "blown castor oil, "blended castor oil," "blended bodied castor oil, "processed castor oil," oxidized castor oil," "heavy castor oil, "viscous castor oil,,etc. These various trade names appear to be applied to drastically-oxidized castor oils which differ merely in degree but not in kind. 4

The color of these oils is still pale or light colored in comparison with the oil from which they have been derived. Usually they are fairly transparent, particularly in reasonably thin layers, for instance, an inch or less. Such oils represent greater or lesser degrees of partial oxidation in the sense that there is a drastic change in comparison with the change that takes place when a film of castor oil is exposed to air.

For the sake of diflerentiation, oils of the kind previously described will be referred to as' pale blown, drastically-oxidized castor oils; and the same terminology is intended to apply to all other ricinoleic bodies of the kind hereinafter described. In addition to pale blown, drasticallyoxidized castor oil. there is also another type of the kind described in U. 8. Patent No. 2,023,979, to Stehr, dated December 10, 1935; The product described in said Stehr patent is characterized by the fact that drastic oxidation is continued past the stage where a pale blown oil i obtained and.

ent No. 2,183,487, dated December 12, 1939, to

Colbeth, to the extent that it discloses details as to the oxidation of castor oil in a manner that is particularly desirable.

Our preference is to subject a pale blown castor oil of the following characteristics, to hydroxyacetylation:

Acid number 15.1 to 25.0 Saponification number 230.5 to 274.0 Iodine number 43.5w 55.0 Acetyl number 164.0 to 192.0 Hydroxyl number 188.0 to 220.0 Percent unsaponiiiable matter 1.1 Percent 803.. 0.0 Percent a Trace The production of hydroxyacetylated blown castor oil or similar compounds is comparatively simple and is comparable to the manufacture of acetylated castor oil, except that hydroxyacetic acid or its equivalent,-such as the anhydrlde or acyl chloride, is employed, and castor oil is replaced by the blown product. In view of the acetyl or hydroxyl valueot blown castorv oil, the principal reaction is obviously an esterlilcation reaction in which the reaction is hastened or caused to go to completion by removal of any water formed. The usual procedures for promotion of esterification are well known, and involve one or more of the following: Employment of a temperature high enough to eliminate any water formed, for instance, 120-180 0.; sometimes the presence of a strong acid, such asa benzenesulfonic acid in small amounts acts as a catalyst: sometimes it is expedient to pass an inert dried gas through the reacting mixture: at other times esterification may be conducted in the presence of a high boiling water-insoluble solvent, such as xylene or the like, which assists in removing the water in the form of vapor; the condensate so derived, both from the water vapor and solvent vapor, is separated y gravity; and the solvent returned to the reacting chamber for further use.

The selection of suitable amounts of reactants in the manufacture of hydroxyacetylated blown castor oil is, of course, simple. The blown oil may be analyzed so as to determine its hydroxyl or acetyl value. Such value may be interpreted on the basis of each fatty acid radical present. The acetyl value or hydroxyl value may not cor. respond exactly to the alcoholic hydroxyl radicals attached to each high molal fatty acid acyl radical, but such value does correspond, at least approximately. The reason is that there may be present anhydrides, or possibly, somecompound of unknown nature or stability, which aflect the hydroxyl value determination. For convenience in the present instance, one may consider blown triricinolein in the same manner that it is sometimes convenient to consider trlricinolein, l. e.. as if it were a trihydric'alcohol, and thus, one may obtain mono-hydroxyacetylated blown triricinolein, di-hydroxyacetylated blown trlricinolein, and tri-hydroxyacetylated blown trirlcinolein. For practical purposes, of course, there is no economical iustiiication for obtaining a technically pure blown triricinolein and subjectin such material to hydroxyacetylation instead of employing blown castor oil.

Thus, the product particularly contemplated in the present instance is the compound or compounds obtained by the hydroxyacetylation of blown castor oil. For purposes of convenience. reference will be made to mono-hydroxyacetylated blown castor oil, di-hydroxyacetylated blown castor. oil, and tri-hydroxyacetylated blown castor oil. Examination of the reaction between hydroxyacetic acid and castor oil, or hydroxyacetic acid and blown castor oil, indicates that water is formed and must be removed. Actually. the water formed may not necessarily be removed instantly, and thus, the water may undergo, certain obvious reactions. Likewise, for reasons of economy, it may be desirable to use a highly concentrated hydroxyacetic acid instead of the anhydrous material as the selected reactant. In such instances, the water would readily enter into hydrolytic reactions with the blown castor oil,

and thus, the productor composition which is. actually hydroxyacetylated, may include compounds comparable to ricinoleic acid, polyricinwoleic acid, mono-ricinolein and diricinolein. Generally, the expression superglycerinated fats, or superglycerinated tricinolein refers to the mixture in which the mono-glycerides and diglycerides are present. Specific terminology indicated in the present instance would be superglycerinated blown castor oil. Likewise, the acids and polymerized acids obtained from the blown castor oil, are sometimes referred to as a blown castor oil estolide. (See U. S. Patent No. 2.079,-

- 762, dated May 11, 1937, to De Groote and Keiser.) In addition to the other products formed by hydrolysis, glycerol must be included.

. It is not intended in the present instance to claim the product obtained by hydroxyacetylation of glycerol, but it is to be noted that such material may be present cogenerically, for reasons indicated. Earlier references to the compounds herein contemplated, and particularly for use as a demulsifier includes hydroxyacetylatedderlvatives of blown ricinoleic acid compounds, and such expression is now suitably qualified "so as to be limited to blown castor oil, blown triricinolein. blown superglycerlnated castor oil, and blown castor oil estolides, and other specific-compounds mentioned subsequently. The preferred example is the cogeneric mixture obtained bythe hydroxyacetylation of blown castor oil. One may employ superglycerinated blown castor oil obtained by reaction between blown castor oil and glycerlne, in the proportion of one or two moles of glycerol per'mole of blown castor oil. This simply means that the product is obtained by rearrangement instead of hydrolysis. Obviously, one may also employ technically pure blown monoricinolein, technically pure blown diricinolein, and technically pure blown ricinoleic acid.

Although'it is believed, in view of what has been said, that no further description is necessary in regard to the manufacture of hydroxyacetylated blown ricinoleic acid compounds, the followins examples are included by way of illustration:

tor oil.

Hudrozyacetylated blown castor cit-Example 1 dure is conducted in the usual reaction vessel of the kind employed for esterification, and may be constructed of any material which is resistant to the reactants. .The amount of hydroxyacetic acid selected in the present instance is calculated so as to give substantially a mono-hydroxyacetylated blown castor oil.

Hydroxyacetylated blown castor oil-Example 2 The same procedure is employed as in Example 1, preceding, except that twice the amount of hydroxyacetic acid is used.

Hydromyacetylated blown castor oil-Example 3 The same procedure is followed as in Example l, preceding, except that three times the amount of hydroxyacetic acid is employed so as to yield substantially a tri-hydroxyacetylated blown cas- Hydrozyacetylated blown castor oil-Example -4 The same procedure is followed as in Examples 1 to 3, preceding, except that anhydrous hydroxyacetic acid is employed and water is-removed immediately upon formation. The product so obtained represents hydroxyacetylated blown castor oil, or more especially, hydroxyacetylated blown triricinolein, in the presence of a minimum amount of hydroxyacetylated cogeners.

It is well known that the exact composition of ordinary oxidized castor oil is not known. This has been a matter of comment from time to time in the literature, including the patent literature dealing with the arts in which blown castor oil is contemplated. In view of such facts, it becomes even more difllcult to attempt to indicate the nature of the products obtained by hydroxyacetylation of blown castor oil or the like. As

has been previously indicated, esterification, and quite frequently, hydrolysis enters into the reacmay be used alone, or in admixture with other suitable well known classes of demulsiiying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oil and water solubility. Sometimes they may be used in a form which exhibits relatively limited oil solubility. However, since .such reagents are sometimes used in a ratio of 1 to 10,000, or 1 to 20,000, or even 1 to 30,000, such an apparent insolubility in oil and water is not sig- --nificant, because said reagents undoubtedly have solubility within the concentration employed. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process. I I

We desire to point out that the superiority of the reagent or demulsifying agent contemplated in our process is based upon its ability to treat certain emulsions more advantageously and at a somewhat lower cost than is possible with other available demulsifiers, or conventional mixtures tion, and it is quite probable, especially when aqueous hydroxyacetic acid is employed, that rearrangement, as exemplified by the formation of estolides, may take place. g

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as gasoline, kerosene, stove oil, a coil tar product, such as benzene, toluene, xylene, tar acid oil, cresol, anthraceneoil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohols, butyl alcohols, hexyl alcohols, octyl alcohols, etc, may be employed as diluents. Miscellaneous solvents, such as pine oil, carbon tetrachloride,'suliur dioxide extract obtainedin the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of our process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents, Moreover. said material or materials thereof. It is believed that the particular demulsifying agent or treating agent= herein described will find comparatively limited application, so far as the majority of oilfield emulsions are concemed; but we have found that such a demulsifying agent has commercial value, as it will economically break or resolve oil field emulsions in a number of cases which cannot be treated as easily or at so low a cost with the demulsifying agents heretofore available.

In practising our process, a treating agent or demulsifier of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various ways, or by any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used either alone or in combination with other demulsiiying procedure, such as the electrical dehydration process.

The demulsifier herein contemplated may be employed in connection with what is commonly known asdown-the-hole procedure, i. e., bringing the demulsifier in contact'with the fluids of the well at the bottom of the well, or at some point prior to their emergence. This particular type oi. application is decidedly feasible when the demulslfier is used in connection with; acidification of calcareous oil bearing strata, especially if suspended in or dissolved in' the acid employed for acidification;

Previous reference has been made to certain specific hydroxyacetylated derivatives of blown ricinoleic acid compounds. These additional members include blown diricinolein, blown monoricinolein, superglycerinated blown castor oil, 1. e., castor oil which has been blown and then superglycerinated, as differentiated from one which is superglycerinated and then blown, and also blown ricinoleic acid and blown polyricinoleic acid.

Having-thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for breaking petroleum emulsions of the water-in-oil type, characterized by sub- Jecting' the emulsion to the action of a demulsifying agent comprising a hydroxyacetylated drastically-oxidized ricinoleic acid compound selected from the class consisting of blown castor oil, blown triricinolein, blown diricinolein, blown .monoricinolein, blown superglycerlnated castor oil, superglycerinated blown castor oil, blown ricinoleic acid, blown polyricinoleic acid, and blown castor oil estolides.

2. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying agent comprising hydroxyacetylated drastically-oxidized castor oil.

3. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying agent comprising mono-hydroxyacetylatecl A drastically-oxidized castor oil.

4. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying agent comprising di-hydroxyacetylated drastically-oxidized castor oil.

5. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifying agent comprising tri-hydroxyacetylated 10 drastically-oxidized castor oil. 1

IWELVIN DE GROOTE. BERNHARD KEISER. ARTHUR F. WIRTEL. 

